1. Field of the Invention
The present invention generally relates to wireless telecommunication networks. More specifically, the present invention relates to a system and method for buffering initial data for direct group communications, such as Push-to-Talk group communications, in a wireless telecommunication network to reduce latency.
2. Description of the Related Art
In a wireless network, the users of wireless communication devices communicate over an air-interface to a central computer. This may be done directly, as in the case of a wireless LAN in an office environment, or it may be done through cellular infrastructure equipment, as in the case of a wireless telephone application. One type of personal communication system is a push-to-talk (PTT) system between mobile wireless communication devices. A PTT communication connection is typically initiated by a single button-push on the wireless device that activates a half-duplex link between the speaker and each member device of the group and once the button is released, the device can receive incoming PTT transmissions once the button is released. In some arrangements, the PTT speaker will have the “floor” where no other group member can speak while the speaker is speaking. Once the speaker releases the PTT button, any other individual member of the group can engage their PTT button and they will have the floor. A specific PTT group of recipient devices for the communicating wireless device is commonly set up by the carrier and the wireless devices themselves do not allow the modification of the group, i.e. to include or drop individuals from the group, or to purposely direct a communication to be received by any fewer members than the entire group.
To set up the PTT call, communication to begins with the press of the PTT button on the handset, as opposed to a standard cellular call, and the infrastructure forms a call by combining separate point-to-point connections between each endpoint at a managing entity, such as a server, deployed on the network carrier infrastructure. For purposes of validating the connection, pressing the PTT button originates provides the person with information indicating the availability (presence) of the target user. If the target user is available, the originator receives an immediate indication (such as an audible tone) that the target user is available and the originator can begin speaking. The call originator's voice is then sent through the carrier's network to the target's handset.
One problem arises in a push to talk system in that the person desiring to speak may press the PTT button and have to wait for an acknowledgement that the wireless telecommunication device can send out the group communication. In a common configuration, the device will not send any message until the active dedicated traffic channel is established, which typically means that communication with the appropriate communication equipment has been established, and at least one member of the target group of wireless devices is available to receive the group communication. If the latency delay to set up the dedicated traffic channel is significant, the person will notice the delay. It is thus to such a system and method of reducing latency for the setup of a PTT or direct group communication that the present invention is primarily directed.